Improvement in cryptography



UNITED STATES PATENT QFFIGE.

ANTHONY LOUIS FLAMM, OF PARIS, FRANCE.

IMPROVEMENT IN CRVPTOGRAPHV.

Specification forming part of Letters Patent No. 166,761, dated August17, 1875 application filed June 25, 1875.

To all whom it may concern:

Beitknown that I, ANTHONY LoUrs FLAMM, ex-major of the Ottoman army, of13 Rue Gaillon, Paris, France, have invented certain new and usefulImprovements in Secret Correspondence and I hereby declare that thefollowing, taken in connection with the drawings which accompany andform part of this specification, is a description of my inventionsufcient to enable those skilled in the art to practice it.

My invention consists in an improved system and apparatus by which asecret correspondence, in the shape ofletters, postalvcards, telegrams,or otherwise, can be carried out, with the usual letters of thealphabet, rapidly, and yet be unintelligible to all outside parties, bymeans of a simple and inexpensive apparatus.

In order that my system and apparatus may be clearly understood, I willproceed to describe the same conjointly with the six iigures of theaccompanying drawing.

My improved cryptograph consists, first, in a tablet, (shown open inplan, Figure 1, in lateral eleva-tion in Fig. 2, and closed in Fig. 3,)divided horizontally and vertically by, say, twentyfive equidistantlines, formf ing,` twenty-four vertical and twenty-four horizontalcolumns, which, by their intersection, produce five hundred andseventy-six squares of equal size-of, say, about one centimeter on aside 5 secondly, in a folding plate of metal or other appropriatematerial, (shown open in plan, Fig. 4, and folded in elevation, Fig. 5,)of the same size and divided in the same manner as the tablet, so thatthe squares of the former correspond exactly with those of the latter 5and, thirdly, in sheets of paper or other similar material, Fig. 6, ofthe same dimensions and divided into squares in the same manner as thetablet and the plate.

An outer frame or border is attached to the tablet, on which are marked,above and below, the figures 1 to 24, corresponding` with the verticalcolumns; and on the two sides are similar figures, corresponding withthe horizontal columns, and, above, the word horizontal, and, on oneside, the word vertical.77 The plate is marked, in each of its fourcorners, with one of the Roman letters I II III IV, and is pierced withone hundred and forty-four holes, which number corresponds withone-quarter' of the squares on the tablet, and these holes are made,according to my system, in such a manner that, by placing the plateexactly over the tablet, and by replacing` it three times successively,turning it each time one-quarter round, either to the right or to theleft, as maybe previously agreed upon by the parties using the same fortheir correspondence, these one hundred and forty'four holes will havecovered the five hundred and seventy-six squares of the tablet. Myinvention consists in the combination and construction of devices, ashereinafter claimed.

As the distribution of the holes in the plate may be varied to an almostunlimited extent, it follows that millions of parties may use myapparatus without the possibility of one deciphering the composition ofthe other, since no two parties would use plates similarly pierced.Suffice it to state that the permutations of the holes in a platecontaining five hundred and seventy-six squares, as above described,amounts to a number represented by no less than eighty-seven figures.

It is barely necessary to state that the same rule applies to atablet ofsmaller or larger dimensionsthat is to say, with a greater or smallernumber of squares-provid ed that the number of horizontal and verticalcolumns are the same, and are both even numbers, thus forming a perfectsquare.

The manner of using my improved cryptograph for written correspondence,such as letters, postal-cards, Src., is as follows: The sender andreceiver bein geach in possession ofan appa-- ratus similar as to sizeand to distribution of the holes, the sender takes a sheet of paper,pre-` pared as described,of the same sizeas the tablet, on which heplaces it. He then covers it with the plate, and writes his epistle fromleft to right, in the usual manner, letter by letter, on theV paper, (orword by word, if desired,) through each successive hole in the plate,commencing` with the upper line, and taking all the other linessuccessively to the bottom of the plate. He then raises the plate, turnsit one-quarter round from right to left, or vice his tablet in acorresponding manner or posiversa, as may have been previously agreedupon, replaces it on the paper, continuing his letteringthrongh the sameholes, but on diiferentparts ofthe paper, and so on, until he haswritten through the plate four times in four different positions. Thiswritten matter, thus prepared for transmission, forms an amalgamation ofletters such as it is impossible for any party to decipher, except thereceiver, or any otherperson whois in possession of an apparatus similarto the one by which it was composed- The receiver simply lays theprepared sheet in tion, covers it with the plate, and, beginning withthe same edge as the sender, reads off successively the letteringthrough the holes as seen under the four different positions of theplate. The cross-lines of the paper sheet, corresponding as they do tothose of the perforated plate, of themselves insure a correctregistering of the two relatively to each other, and afford a suresignal or indication to the eye of the writer or reader ofthe message,in case the two should 'accidentally got out of register, so that theymay, if desired,be used without the frame or raised border of thetablet. For instance, if the perforated plate be laid upon thecross-lined sheet, and the latter held by pins in its proper relation tothe former, and there should be any accidental straining or displacementof the paper upon its pins during the manipulations or turnings of thepaper, or if the two should be applied to each other when the light issomewhat dim, and with a consequent liability of not placing all theedges ofthe paper and the plate so as to register, then the rst attemptto write within any perforation, or to read through any and everyperforation, would betray, through such perforations, theselcross-lines, and thus give visible proof that vthe registering isincorrect; for when it is correct all the lines of the paper will behidden beneath the non-perforated parts of the plate. In short, thelines of the paper afford a `complete and sure registeringguide, eventhough the paper be of much larger area than the plate, or be of anirregular shape. The lines, also, much facilitate the reading of themessage by the person receiving it, as the alignment of the words andsentences is'more readily apparent.

The man-n er of usin g my cryp tograph for telegraphic purposes is asfollows: The sender cuts Y oiffrom the prepared papera strip containingsuch a number of vertical columns as may be required for his telegram,(for the convenience of reckoning it is preferable to adopt rows offive, ten, fifteen, 8tc.,) writes his dis themselves successively on theplate, being used four times, and turned one quarter at each applicationexcept the rst one, continuing thus until the last letter of the lastcolumn has been transcribed.

The receiver, who is in possession of an eX- actly similar apparatus,and acquainted bothwith the size of paper adopted and its position onthe tablet, takes out a similar strip, places it in the same posit-ionon his tablet,

covers it with the perforated plate, and Writes it in, as previouslydescribed with regard to the written correspondence. On raising theplate after ithas been used in its four diiferent positions, thedispatch will be read correetl y transcribed.

I do not claim, broadly, the employment of a square plate marked oil'into squares, a-portion of which are perforated, and arranged to beturned or rotated to be in connection with a plain or unprepared sheetof paper, for cryptographic purposes, as these have been heretoforeused; but

What I claim as my invention is 1. As an improvement in cryptographicapparatus, the combination, with the perforated plate, Fig. 4,cross-lined to form squares, of

the paper sheet, Fig. 6, prepared with eorrevspending squares,substantially as and for` the purpose set forth. Y

2; The folding and framed tablet, provided 011 its horizontal andvertical margins with the serial numbers, in combination with theperforated plate and prepared-paper sheet, substantilaly as and for thepurpose set forth.

3. In combination with the subject-matter of the above second clause ofclaim, the exterior wrapper or cover, as described and shown.

ANTHONY LOUIS FLAMM.

Witnesses:

RoB'r. M. HooPER, D. H. BRANDON,

13 Rue Guillon, Paris.

